diff --git a/engine/common/imagelib/img_main.c b/engine/common/imagelib/img_main.c
index 919143db..70e67ce1 100644
--- a/engine/common/imagelib/img_main.c
+++ b/engine/common/imagelib/img_main.c
@@ -13,6 +13,7 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
 */
 
+#include <math.h>
 #include "imagelib.h"
 
 // global image variables